96 CALIFORNIA ACADEMY OF SCIENCES 
[Proc. 4TH Serr. 
Mr. Gifford remarks in his notes that the bill and orbital 
ring are black, the iris dark brown, the lower parts of the feet 
black and the remaining parts pinkish white. 
Six specimens of Pterodroma cervicalis, two of them emerg- 
ing from the natal down, and the Expedition series of Ptero- 
droma externa show the following differential characters: 
P. externa 
Cap dark brownish gray, fading 
into grayish brown in worn plum- 
age. 
No definite cervical collar. 
First primary extensively white 
on inner web. 
Only indications of dark band 
on inner edge of wing. 
Dark color of tail (except outer- 
most web) brown, washed with 
gray in fresh plumage and forming 
definite tips to outer feathers, 
Shafts terminally black or dark 
brown in all the tail feathers. 
P. cervicalis 
Cap brownish black. 
Definite cervical collar white, 
clouded with gray. 
First primary with little or no 
white on inner web. 
Dark band, varied with white, on 
inner edge of wing. 
Dark color of tail gray, not form- 
ing definite tips to outer feathers, 
and fading into grayish brown in 
worn plumage. 
Shafts not terminally black or 
dark brown in all the tail feathers. 
MEASUREMENTS (in millimeters) 
No. Sex | Length } Extent | Wing 
MU ee 470 | 1092 | 336 | 150 
1118 | o 457 | 1074 | 328 | 146 
1120 | of 435 } 1015 |..... 146 
1123 | o 444 | 1029 |..... 138 
DDS sa | ee ieuel al ae aan 316 | 133 
LAD ORIG alte Ree 313 | 138 
1127 | o 444 | 1054 | 320 | 134 
1128 | o 437 | 1067 | 314 | 145 
1129 | of 432 | 1041 | 309 | 139 
1130 | o 457 | 1054 | 327 | 145 
1119 | 9 449 | 1067 | 320 | 138 
1121 | 9 439 | 1067 | 316 | 132 
1122 |} 9 444 | 1054 | 323 | 135 
1A UI. SF OA Meas Ava Pal Lea 134 
1131 | 9 432 | 1041 | 313 | 138 
Tail 
Upper Mandible Middle 
Culmen ‘arsus |Toe and 
Depth | Width Claw 
37.4 | 14 18 37.4 | 55.9 
38.4 | 12.9 | 17.1 | 36.1 | 54.8 
39.9 | 13.7 | 17 36 50.5 
36.9 | 12.9 | 17 33.1 | 49 
38 13.4 | 18 35.7 | 52.1 
einen 12.6 | 17.4 | 34.3 | 52.2 
39.1 | 12.8 | 17.7 | 37 50 
37 14.2 | 19 37.6 | 50.6 
36.5 | 12.7 | 17.1 | 37 53.9 
39.1 | 13.8 | 18.5 |} 35 $1 
38.3 | 13.4 | 18.1 | 37 52.2 
37.5 | 12.9 | 16.1 | 36.1 | 53 
36.2 | 12.3 | 15.5 | 33.4 | 47.7 
39 12.8 | 16.8 | 35.9 | 49.8 
35.3 | 12.9 | 16.4 | 34.6 | 50 
